grillzHi Eydok,
Obviously, I don't know you but you might appreciate knowing what you're in for and what you might be able to improve on.
It will be easier to generate TF2 viewers if you have a deep understanding of the game. I suppose this is like any other game but TF2 can be a little different. The success of our TF2 casters balances on their ability to comment on the game play. Why a push was unsuccessful, what a team has to change to win or why the medic just made a game-breaking play. If you listen to any of Extine/sal/cbear/djc/etc casts you'll notice how well they fill gaps with some informative analysis. It can be make or break whether a viewer appreciates your casting or not. Especially if you talk a lot but its clear you're not really sure whats going on. I would suggest working on that first until you feel as though you can really add something rather than simply casting what is happening. Otherwise you might get a lot of negative response and people will be less likely to tune in again.
It is also important to keep an eye out for critical points in the match. Back caps, bombers, dropped ubers, off-classing (people especially like to watch spy). This is a huge perk of having multiple casters... the extra set of experienced eyes can predict when these critical points might happen. This prediction and foresight allows you to switch the camera while explaining to your viewers whats going on and why it is (or might be) exciting. Sometimes this can all happen in a matter of seconds.
Anyway, good luck
edit: I realize you weren't posting here for 'shoutcasting tips' but like I said, tf2 can be different. If you can perfect it, viewers will be easier to sustain and you wouldn't seem so anonymous to the community.
Thanks for the tipp mate. Now i might not be an expert player, but i have played about 4th division so i still know the "basics" of the game. It will take me more time to refresh my memory on tactiques (since i have been doing alot of CSS and LOL shoutcasting) but in the end i will be able to pull it off. I know it.